Case Report
Surgical Management of Cerebrospinal Fluid (CSF) Otorrhea Presenting as CSF Rhinorrhea: Different Approaches
Mehta Madhuri*, Morwani KP and Arsiwala Zainab
Department of Ent, N.C. Jindal Institute of Medical Sciences, India
*Corresponding author: Mehta Madhuri, Department of Ent, N.C. Jindal Institute of Medical Sciences, Hisar Haryana, India
Published: 24 Apr, 2017
Cite this article as: Madhuri M, Morwani KP, Zainab A. Surgical Management of Cerebrospinal Fluid (CSF) Otorrhea Presenting as CSF Rhinorrhea: Different Approaches. Ann Clin Case Rep. 2017; 2: 1395.
Abstract
CSF otorrhea though a rare clinical entity, is a life threatening situation that requires rapid intervention. Though occurring through the otologic structure, actual leakage from the ear may not always be present (unless the ear drum or canal is in some way violated), but the fluid may flow down the Eustachian tube and manifests as a clear fluid through the nose. The presence of an abnormal communication of the sterile subarachnoid space with the flora of the sinonasal tract, places the patient at a great risk of meningitis. Diagnosis of such cases, need a high index of suspicion, complete clinical examination of nose and ear and relevant investigations to avoid unnecessary nasal exploration and prevent life threatening meningitis. This case report presents the diagnosis and management of two cases of CSF otorrhea presenting as CSF rhinorrhea, one having a spontaneous leak, and the other following trauma. Mention is made of how one could subject a patient to inadequate surgery, if one is not vigilant and adequate investigations are not carried out. Different methods of repair depending on the site and size of defects are outlined in the two different cases. Consent was obtained from each case in the format mentioned towards the end.
Introduction
CSF leak can occur when there is disruption in the arachnoid and dura mater coupled with
an osseous defect and a CSF pressure gradient that is continuously or intermittently greater than
the tensile strength of the disrupted tissue [1]. The aetiological factors for CSF leaks in mastoid
include otologic or skull base surgery, trauma, tumors and spontaneous –idiopathic and congenital
dehiscence [2]. Complication of Skull base surgery is the most common cause of CSF otorrhea,
followed by temporal bone fractures (21%). Spontaneous leaks are extremely rare with only 500
cases being reported in literature worldwide. Traumatic leaks are commonly seen following road
traffic accident associated with other multiple injuries and hence diagnosed at a later stage once
the patient recovers neurologically. Most common site for dural defect is the tegmen plate. This
defect in the dura mater around the temporal bone defect can transmit the CSF into the mastoid
air cells which may percolate down the Eustachian tube into the nasopharynx when the ear canal
and tympanic membrane are intact. Patients may complaint of unilateral nasal fluid drainage that is
worse after waking up or when bending over.
Diagnosis is based on a high index of suspicion, complete clinical evaluation, and radiological
imaging and/or laboratory studies. High resolution CT scan is sufficient to locate the site or sites of
CSF leaks. MRI is useful in demonstrating meningocele or meningoencephalocele when associated
with CSF leak, as well as for examining patients with spontaneous intracranial hypotension syndrome.
MRI is also required in post-surgical cases to differentiate brain tissue from cholesteatoma or
inflammatory tissue in mastoid cavity. Management consists of wide surgical exposure, amputation
of necrotic, herniated part of brain or meninges with fine bipolar cautery and finally repair of dura
mater and the defect in temporal bone in layers. Though various reconstruction techniques with
different approaches have been described in the literature, an individualized approach should be
taken for each case depending on different factors. The approaches can be classified into otological,
neurological and combined. Each approach has specific advantages and final choice is made taking
into consideration factors like the position and size of the defect on preoperative imaging, the
aetiology of meningoencephalocele, and the preoperative audiometry.
Case Presentation
Case 1
A 62 years old obese female patient presented with the chief
complaints of spontaneous, intermittent, unilateral, clear watery
nasal discharge from left nostril since 4 months which was worse on
waking up and bending forwards. She also had two episodes of fever
associated with vomiting and giddiness which subsided with a course of oral antibiotics. She complained of decreased hearing in the left
ear, of the same duration as that of the nasal discharge.
Fluid sample was collected and chemical analysis for glucose
and beta2 transferrin was positive, consistent with CSF. Computed
Tomography (CT) scan of the Para nasal sinus (PNS) showed postsurgical
changes but no defect in anterior skull base (Figure 1A) which
could be a potential site of leak, and audiogram showed a moderate
conductive haring loss in the left ear. Patient had consulted a surgeon in the past, who had carried out left sided functional endoscopic
sinus surgery in order to look for the site of leak, in spite of normal
high resolution CT scan of Para nasal sinuses (Figure 1B), but as no
defect was found, and patient had persistent CSF leak even post nasal
exploration, the patient consulted us. In view of persistent CSF leak
through the nose, a normal CT PNS (prior to nasal exploration),
and hearing loss, we were directed for radiological assessment of
the temporal region. CT scan of the temporal bone revealed a defect
in the tegmen tympani with opacification of the left middle ear by
fluid and soft tissue (?Meningoencephlocoele) (Figure 1C and D). Endoscopic examination of left nostril revealed evidence of post
endoscopic sinus surgery changes with CSF leak from nasopharynx
area. Microscopic examination of left ear revealed intact tympanic
membrane. Decision was taken to explore the left middle ear and
mastoid via a transmastoid approach.
Surgical steps (left ear): Cortical mastoidectomy was performed.
CSF leak was found from the defect which was in the medial portion
of tegmen tympani and antri in the region just superior and anterior
to the head of malleus and body of incus. Through the defect
herniated necrotic brain along with meninges could be visualized.
Hypertrophied mucosa and granulation tissue was seen around
the ossicles and tegmen, along with hyper cellularity in that region
(Figure 2A and B). Lateral wall of antrum and posterior attic was
drilled away to expose the meningoencephlocoele. Gentle bipolar
cauterization of the herniated brain was done (Figure 3A) to reduce
its size and reach the anterior extent of meningoencephlocoele which
was reaching anterior and medial to head of malleus and body of
incus (Figure 3B). The incus and head of malleus removed gently
and meningoencephlocoele was exposed in its anterior most extent
(Figure 4A and B). Reduction of rest of the meningoencephlocoele
towards the middle cranial fossa was performed with fine bipolar cautery (Figure 5A) and the defect in tegmen exposed completely (Figure 5B). As the size of the defect was <2 cm x 2 cm and located in medial part of tegmen plate, cartilage graft was chosen for repairing
the bony defect which was in two dimensions. It’s worth mentioning
here that bone graft being stiff and non-malleable could not be used
in this case.
The complete defect was repaired in 4 layers. As it was a
meningoencephlocoele, an extra layer in the form of free muscle graft
was used. A piece of muscle was harvested from the post auricular
region which was about one and a half times the size of the defect and
was carefully tucked into tegmen defect. The muscle layer was then
covered with the temporalis fascia graft which was also gently tucked
underneath the tegmen (used to replace the defect in the dura) and
sealed with tissue glue. These layers were then secured in place by
a large piece of tragal cartilage (bigger than the size of the defect), carefully tucked in the defect of the tegmen in all directions. This was
then finally covered with temporalis fascia again and then covered
with tissue glue (Figure 6A, B and C).
The patient was followed postoperatively on day 7 and 21 after
discharge, then 3 monthly for the first year, 6 monthly in the second
year and has been asked to stay on long term follow up at least once
yearly. There is no recurrence of CSF leak either through the nose or
ear, and hearing of the patient has returned to near normal. The postoperative
HRCT temporal bone showed repair tissue in place (Figure
7A and B) and otoendoscopy showed intact tympanic membrane
(Figure 7C). After a 15-months follow-up the patient remains
symptom free and no recurrence is noted.
Case 2
A 27 year old boy came with complaints of clear, unilateral watery
nasal discharge on left side, 2 months following head trauma. Patient
had no neurological deficit following trauma. Patient also had no
complaints of giddiness though he was having mild hearing loss on
the left side. Computed tomography scan of the paranasal sinuses was
done which was normal. In view of a normal CT PNS and clear watery
nasal discharge with an intact tympanic membrane left side, decision
was taken to do a CT scan of the temporal bone. CT revealed a defect
in the region of tegmen antri left side (Figure 8A and B), and hence a
decision of doing an exploratory mastoidectomy was taken.
Surgical steps (left side): The tympanic membrane was found
intact and cortical mastoidectomy showed active CSF leak from
defect in tegmen antri and tegmen mastoideum near its lateral
portion superior and posterior to the ossicles (Figure 9A and B). So
ossicles were not disturbed. Tympanomeatal flap had to be lifted to look for cause of mild conductive hearing loss (Figure 10A). Fracture
line could be seen extending from tegmen bone to posterior bony
canal wall (Figure 10A). There were adhesion bands around intact
ossicular chain which were released (Figure 10B).
The meningoceole was gently bipolarised and defect in tegmen
antri was localised in its lateral part (Figure 11A). The linear fracture line was extending from lateral to medial part of tegmen antri. The dura was separated from around the margins of defect so as to assess
the exact size and extent of defect (Figure 11B). The assessment of
the size of the defect was done, which was around 2 cms x 2.5 cms.
As the defect was laterally placed and size was more than 1cm [2],
the transmastoid approach was combined with mini middle cranial
fossa approach and an autologous bone graft from the temporal
craniotomy was used in place of cartilage graft to cover the tegmen
defect.
The defect was repaired in three layers. As it was only meningocoele
with no brain tissue, the muscle layer was omitted. The reinforcement
of dura was done with temporalis fascia and bony defect was repaired
with squamous temporal bone graft. For harvesting bone graft, the
squamous temporal bone was exposed by elevating the superficial
temporal muscle. A craniotomy of size 3 cms x 3.5 cms was drilled
in the squamous temporal bone. Inferiorly the craniotomy reached
few mms above the tegmen margin so as to minimise the degree of
temporal lobe retraction. Anterior extent was up to base of zygoma
and posterior extent was up to sinodural angle so as to cover and reach
beyond the defect in tegmen plate in all dimensions. The craniotomy was performed with a medium sized cutting burr first and small sized
diamond burr in final stages, when we reached close to dura, so as to
avoid any injury to dura. The bone graft was slowly separated from
the underlying dura after completing drilling the margins.
The middle cranial fossa dura was then carefully separated from
the tegmen bone from middle cranial fossa side, around and beyond
the complete circumference of defect so as to create space for placing
the fascia and bone graft. The first layer which was temporalis fascia,
harvested at the start of the operation, was placed from middle
cranial fossa side to repair the dura (Figure 13A). The fascia layer was
reaching beyond the defect in all dimensions. Fibrin glue was used in between the layers (Figure 13B).
After spreading the fascia graft, for second layer, the already
harvested autologous bone graft is placed from middle cranial fossa
side between the temporalis fascia graft and tegmen bone (Figure 14A
and B). It covered the defect in bone and reached beyond the defect
in all dimensions (Figure 14C). The third layer was with temporalis
fascia which was again tucked in around the defect from mastoid side
(Figure 15A and B). Fibrin glue was again used to seal the defect with
all layers (Figure15C). Post operatively patient was examined on 7th
and 21st post-operative day. After that regular follow up was carried
out every three months for one year. The HRCT scan temporal bone
was carried out after one year. Post-operative CT scan showed bone graft in place (Figure 16A and B) and post-operative otoendoscopy showed intact tympanic membrane (Figure 16C). One year post surgery, the patient is completely symptom free with no recurrence
of CSF leak through nose or ear and his hearing has returned to near
normal.
Figure 1A
Figure 1B
Figure 1B
HRCT Para nasal sinuses prior to endoscopic sinus surgery,
coronal cuts showing normal sinuses with no anterior skull base defect.
Figure 1C
Figure 1C
HRCT temporal bone, axial cut showing defect in the tegmen
tympani in the region of attic with opacification of antrum and middle ear.
Figure 1D
Figure 2A
Figure 2A
Showing meningoencephlocoele in the region of attic. Tympanic
membrane found intact (black arrow).
Figure 2B
Figure 3A
Figure 3A
Bipolar cauterization of meningoencephlocoele to reduce the
size and reach margins of tegmen bone defect in all dimensions.
Figure 3B
Figure 3B
The anterior extent of meningoencephlocoele which is reaching
anterior and medial to head of malleus and body of incus( black arrow).
Figure 4A
Figure 4A
Incus and head of malleus being removed , to reach anteriormost
extent of the bony defect.
Figure 4B
Figure 5A
Figure 5B
Figure 6A
Figure 6B
Figure 6c
Figure 7A
Figure 7A
Post-operative HRCT temporal bone A: axial cut showing repair
of defect in tegmen and ossiculoplasty with head of malleus over head of
stapes (yellow arrow).
Figure 7B
Figure 7B
Showing repair of tegmen with cartilage (black arrow) which
cannot be differentiated from surrounding soft tissue.
Figure 7c
Figure 8A
Figure 8B
Figure 8B
HRCT temporal bone showing tegmen defect (yellow arrow) in
axial cuts with opacification middle ear.
Figure 9
Figure 9
Defect in the tegmen antri and tegmen mastoideum with
active CSF leak (black arrow). Intact tympanic membrane can be visualised
(white arrow)
Figure 10A
Figure 10A
Tympanomeatal flap (TMF) is lifted. Fracture line running from
tegmen plate to posterior bony canal wall can be visualised (white arrows).
Figure 10B
Figure 10B
Tympanomeatal flap (TMF) is lifted. Fracture line running from
tegmen plate to posterior bony canal wall can be visualised (white arrows).
Discussion
CSF leakage otorrhea can be either acquired or spontaneous.
Acquired causes which are more frequent include skull base surgery,
trauma and tumors, whereas spontaneous which are very rare can
be either due to congenital defects in the tegmen or dehiscence of a
congenitally thin tegmen either due to raised intracranial pressure or
arachnoid granulations.
Children are subject to spontaneous CSF otorrhea, and it can
be detected with congenital disorders, such as Mondini anomaly,
patent cochlear aqueduct, patent Hyrtl fissure, patent petromastoid
canal, and patulous facial canal [3]. Spontaneous CSF otorrhea can
be also detected in adults, and it occurs when the bone matrix, which
is between the middle ear and the intracranial space, is abnormal. As
temporal bone develops there may be congenital deficiency within
the skull bones which over the time keeps persisting. With every heart
beat there is thrust of brain on these weak areas. The pressure keeps on
building over the years leading to remodelling of weak bones finally
presenting with herniation of brain and meninges with or without
CSF leak, in to mastoid air cells. These leaks can be single or multiple depending on sites of weak areas. Other causes for spontaneous leak
can be, a defect in the annular ring of the stapes footplate resulting
in drainage of CSF into the middle ear. Similar presentation may
be observed in a patient with widely patent cochlear or vestibular
aqueduct, abnormal patency of petro mastoid canal or patent Hyrtl
fissure. CSF may propagate along the fallopian canal and can leak
adjacent to the facial nerve [4].
In such situations, as the tympanic membrane is intact( unless
patient is suffering from otitis media with perforation of membrane)
patient usually presents with CSF rhinorrhea. When we get a
normal CT Scan paranasal sinuses, in case of CSF rhinorrhea, a high
resolution CT Temporal bone is required to look for defect in tegmen
bone with or without meningoencephalocele.
In post-traumatic CSF otorrhea presenting as CSF rhinorrhea,
we may find additional fracture lines on high resolution CT scan
temporal bone. Localization of an otogenic CSF leak is accomplished
using high resolution CT scan with axial and coronal sections, and
unless an otologic source is certain, the scan should cover all 3
cranial fossae [4]. MRI is usually required in post-surgical cases to
differentiate brain tissue from cholesteatoma or inflammatory tissue
in mastoid cavity.
An individualized approach should be taken for repair of
temporal bone cerebrospinal fluid leaks. Various reconstruction
techniques with different approaches have been described in the
literature. The approaches can be classified into five varieties naming:
transmastoid, transmastoid with mini middle cranial fossa approach,
transcranial intradural, combined transcranial/transmastoid and
finally, obliteration of mastoid cavity and middle ear with cul-de-sac
closure of external auditory canal.
Each approach has specific advantages and final choice is made
taking into consideration factors like the position and size of the defect
on preoperative imaging, the etiology of meningoencephalocele, and
the preoperative audiometry. The transmastoid approach provides
information about the precise size and location of the dural defect and
is alone sufficient in case leak is small (<1 cm2) and closer to medial
part of tegmen plate. Here tragal cartilage graft is used to repair bone
defect and temporalis fascia is used to reinforce dura mater.
It’s combined with mini middle cranial fossa approach [5] to
repair the defects which are bigger than 1 cm2 but less than 3 cm2. In
this approach the squamous temporal bone graft is used to repair the
bone defect and temporalis fascia to repair the dural defect. In mini
middle cranial fossa approach, as the name suggests, a craniotomy
is performed to harvest squamous temporal bone graft, though its
dimensions are smaller and more posteriorly based than those of the
conventional middle cranial fossa approach. The principle is that the
size of craniotomy can vary according to the site and size of defect.
If the size of defect is even bigger and there is associated profound
hearing loss (as these cases are usually post traumatic with multiple
injuries), the mastoid may need to be obliterated with fat. Obliteration
of the middle ear and Eustachian tube may also be required, especially
if the leakage is not limited to the mastoid [6]. If diffuse leak is
observed from multiple mastoid air cell tracts the approach remains
complete obliteration of mastoid cavity and middle ear with cul de sac
closure of external auditory canal.
A primary transcranial approach is needed for defects that are
very big sized, multiple, located in the petrous apex, and in revision cases. In Trans cranial intra dural approach, two extra layers of
artificial dural graft are placed. First layer of artificial dural graft is
with Duragen (size 5.0 cm × 5.0 cm) placed extradurally between dura
and cartilage graft and second layer of artificial dural graft (Duragen
size 2.5 cm × 2.5 cm) is used to cover the dural gap intra durally
between inner surface of dura and brain. Intradural graft placement is
generally preferred in such cases, as it guarantees repair of meninges
after cauterising the protruding part in mastoid cavity. And possibly
in revision cases, it ensures, that the infected parts of cortical contents
are not pushed intra cranially. Such a graft placement also facilitates
better resistant to intracranial pressure [7].
Figure 11A
Figure 11A
Meningocoele was gently bipolarised. Linear fracture line with
defect in tegmen antri in lateral part is visible (black arrows).
Figure 11B
Figure 11B
Dura was lifted from the margins of defect to assess the exact
size and extent of defect.
Figure 12
Figure 13A
Figure 13B
Figure 14A and B
Figure 14A and B
Second layer of squamous temporal bone being placed
via the middle cranial fossa approach.
Figure 14C
Figure 15A and B
Figure 15A and B
The third layer of repair with temporalis fascia tucked into
and all around the defect from mastoid side.
Figure 15C
Figure 16A and B
Figure 16A and B
Post-operative scan showing graft in situ in A: axial and
B: coronal cuts (yellow arrow)
Figure 16C
Conclusion
CSF rhinorrhoea may not always be due to anterior cranial fossa defect. High index of suspicion with thorough history and relevant investigations will lead to correct diagnosis and management of CSF leaks that present as nasal leaks but having an otologic origin.
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